WASHINGTON – A series of gas explosions damaged at least 23 buildings and residences in several Massachusetts towns and there have been reports of injuries, state authorities said on Thursday.

The incident began about 5 pm when several explosions occurred in buildings in the towns of Lawrence, Andover and North Andover.

The reason for the blasts, so far, it unknown.

Massachusetts state police confirmed to reporters that at least 23 explosions and subsequent fires had occurred at a number of different addresses, although local media reported that more blasts had taken place in nearby areas.

The fires were attributed to possible problems with the natural gas system and security forces urged local residents to leave their homes immediately if they smell gas or suspect that they could catch fire.

Local media reported that local fire chief Michael Mansfield said that between 25 and 30 active fires were being battled in Andover and at least 18 more in Lawrence.